How does phenol in oral analgesic chemically relieve the pain??

Answer 1

Phenol is not present in a pure state but in a combined form, the active species, the phenoxide ion blocks the pain signals.

Answer 2

Occasionally, pain related to nerve injury can be treated by injecting a caustic substance, such as phenol, into a nerve to destroy it, by freezing the nerve (in cryotherapy), or by burning the nerve with a radiofrequency probe. These techniques may be used to treat facial pain due to trigeminal neuralgia.

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